feat(model-api): add getOriginalReference() function

Author: mhuster23

model-api/src/commonMain/kotlin/org/modelix/model/api/INode.kt

@@ -22,6 +22,7 @@ import kotlinx.coroutines.flow.flatMapConcat
 import kotlinx.coroutines.flow.flattenConcat
 import kotlinx.coroutines.flow.flowOf
 import org.modelix.model.area.IArea
+import org.modelix.model.data.NodeData
 
 /**
  * Representation of a model element.
@@ -206,6 +207,11 @@ interface INode {
     @Deprecated("use getReferenceLinks()")
     fun getReferenceRoles(): List<String>
 
+    /**
+     * @return the original reference of this node
+     */
+    fun getOriginalReference(): String? = getPropertyValue(IProperty.fromName(NodeData.ID_PROPERTY_KEY))
+
     // <editor-fold desc="non-string based API">
     fun usesRoleIds(): Boolean = false
     fun getContainmentLink(): IChildLink? = roleInParent?.let { role ->